| The fiber coalescence separation method not only has high efficiency,but also need less energy,It has aroused wide attention of domestic scholars,many scholars have researched the influence of emulsion flow rate,initial moisture content,effect of fiber surface properties,bed structure on coalescence separation efficiency,but the water droplets coalescence process on the surface of fibers in the emulsion is very complex and difficult to display,so the coalescence mechanism has not formed a consensus and the influence of the same factor on the separation efficiency is not uniform,even contradictory.In this paper,the wetting and collision coalescence process and mechanism were analyzed through the micro channel device and high-speed photography and the preliminary mechanism analysis was made.The influence of initial water content,flow velocity on the pressure drop and separation efficiency was predicted,meanwhile the prediction was confirmed by a fiber filament in this research.Firstly glass fiber and bamboo fiber were selected as representatives of hydrophilic and hydrophobic fibers.The micro channel device and fiber filament were designed and made by hydrophobic organic glass,the preparation method of quality emulsion which can meet the experimental condition was acquired to lay the foundation for the relevant coalescence mechanism experiment.Secondly,the process which water droplets were intercepted and captured by fibers in water-in-oil emulsion was achieved by the micro channel and high speed photography system.The result shows that the collision coalescence and spreading coalescence existed at the same time when it was hydrophilic glass fiber,while there was only collision coalescence when it was hydrophobic bamboo fiber.It still could not spread on the surface of glass fiber when the water droplet' diameter was small.When the flow rate was low and the water droplet diameter was big,the glass fiber has great interception capabilities.When it was hydrophobic bamboo charcoal fiber,the result shows there were three types of collision in water-in-oil emulsion: two water droplets in emulsion coalescing,water droplet which was captured by the fiber colliding and coalescing with the water droplet in emulsion,two water droplets which were both on the surface of the fiber coalescing,when angle of the emulsion flow direction and the fiber was in 51-70°,the average diameter of water droplet was maximal,the maximum value was 26.25?m,the cross fiber was symmetrical on the emulsion the flow direction,the average value of detaching water droplets' diameter was maximal,the maximum value was 45.65?m,meanwhile the result shows that part of the water droplets was detained by fibers and the remaining water would occupy fibers' surface to reduce the porosity and increase pressure drop.At last,this research investigated the influence of initial water content,flow velocity on the pressure drop and separation efficiency of coalescer filled by hydrophobic bamboo charcoal fibers.The result shows that the separation efficiency was high when the water content and the flow velocity were low,when the flow rate was 1 mm/s and the initial water content was 3%,the separation efficiency was up to 60%,the morphology of the water droplets at the entrance,middle and exit of fibrous bed was analyzed by microscope,the largest diameter of water droplets was found at the exit.It indicates the water droplets leaving from the fibers could be captured and collided with other water droplets again... |
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